Big Hero 6: The Crossover

Chapter 13: A space-time anomaly

Tadashi stands in front of the building, suddenly feeling squeamish. San Fransokyo Correctional Facility looms over him in big, fat, bold white letters. As he and GoGo wait for Wasabi to park his car, he stares ahead through the gate that leads into the prison. The last time he saw Callaghan he was dressed as the supervillain known as Yokai. Tadashi didn't understand his need to be so incognito. Granted what they were doing wasn't very legal, but the villainous wardrobe was over the top in his opinion. But as long as they got Abigail back, he went along with whatever eccentricities Callaghan had.

He wants to believe this Callaghan had similar intentions, but the bold, capitalized letters that spell out the name of the prison say otherwise.

"You doing okay?"

Tadashi tears his eyes away from the gate to address his stoic friend. "Yeah, yeah. I'm good. Peachy, in fact." GoGo raises an eyebrow at him. "Okay, I'm not peachy. This is just…"

"Weird?"

He scoffs. "That doesn't even begin to describe this. And I know that's not saying much considering me being from another universe is weird in itself, but never in my wildest dreams would I have imagined visiting one of my professors at a prison. When I last saw Callaghan, I was helping him build the portal. The only thing we did wrong was build a hazardous interdimensional machine on campus without permission. Not to mention I had to hide this from my friends and family. And I know that sounds bad, but all we were trying to do was save a little girl."

"Little girl?"

"Abigail."

GoGo pops her gum. "You really are from a different world, aren't you?"

"Why? Does this Callaghan not have a daughter?"

Before she can answer, the gate to the prison opens. A young woman steps out and stops in front of the college students. And although Tadashi's never seen her in his life, she looks familiar.

Turning to GoGo, she smiles. "GoGo! It's good to see you."

"You, too, Abigail. How have you been?"

Tadashi inadvertently gawks at the brunette. This is Abigail?! But that can't be right! The Abigail he knows is a six-year-old girl with blonde hair and pigtails! Well, some people's hair changes color as they grow up—but that's not the point! This world is more backwards than he initially perceived.

"Are you one of my father's former students?"

Tadashi tries to smooth over his surprised expression into something more pleasant, but it feels more like a grimace. GoGo comes to his rescue and pulls the strings on his borrowed hoodie, covering his face. Their Tadashi is still dead, so it wouldn't do for someone to recognize him and freak out.

"He's a transfer from New Kyoto Tech," GoGo lies effortlessly. "He just happens to be an admirer of your father's work."

"Oh. Well, I'm glad some people still see him as a respectable scientist." Abigail's smile melts away and is quickly replaced with a grimace of her own. "The university has asked me to return all his academic awards, and they sent me the picture that was hanging in the foyer of the robotics lab."

GoGo frowns in sincere sympathy for the older woman. "Sorry, Abigail."

"Dad founded the Laws of Robotics. He's helped people all over the world with his inventions. Now whenever someone even mentions the name Callaghan, the only thing they see is a villain." Abigail's hands squeeze her purse. "And it's all my fault."

"No, it's not." Tadashi pulls his hoodie back down, despite GoGo's warning glances. "You shouldn't blame yourself for any of this. Science is full of risks. You both knew that going in. Whatever choices he made, it's his responsibility to shoulder those burdens, not yours." He thinks back to the moment right before he got sucked into the portal, when he saw that the intruder was Hiro, and he was five seconds away from losing him forever. He doesn't regret trying to help Callaghan, even if he can't see Hiro again. He'd do it again in a heartbeat if it means Hiro and Abigail are safe. "I know Callaghan's not truly bad. Yeah, he did bad things, but only because he lost something truly precious to him. I'm sure he would have given away all his awards if it meant getting you back. I know I would."

Abigail stares at the stranger, astounded. But ever so slightly, the scowl on her face transforms into a grateful smile, her blue eyes glistening with tears. "Thank you. You don't know how much it means to me to hear someone say that." The moment is disrupted by the buzz of a vibrating phone, and the young brunette breaks eye contact to check her cell. "I've gotta run. It was nice meeting you. And it was great seeing you again, GoGo." With a wave goodbye, Abigail walks into the parking lot.

GoGo turns to him, her expression once again impassive. "I'm finding it harder to believe you're not our Tadashi."

"Why's that?"

"Because he would have said the same thing. Tadashi didn't hold grudges, and I'm sure he would've forgiven Callaghan despite everything he's done."

"So Callaghan really started a fire just to steal Hiro's invention? Why didn't he just ask for help?"

GoGo crosses her arms and leans against the gate. "No one knew if Abigail was even still alive. After she got lost in the other dimension, Callaghan went nuts. Apparently he'd been plotting his revenge against Krei for a while because the incident happened before the showcase. He was beyond reason by that point. None of us could have known, but if we had maybe we could have helped…" Her hands dig into her arms, and Tadashi winces. No matter how emotionless GoGo appears, she can still be easy to read.

"I'm sorry, GoGo. I shouldn't have asked you guys to take me here."

She punches his arm. "Don't apologize. Callaghan's the only one who can help us, so it's not like we have much of a choice. Besides, you're our friend. It doesn't matter what dimension you're from. We'll always be here for you, Tadashi."

The young man rubs his bruised appendage. "Ow. And thanks."

A few minutes later, Wasabi finally joins them. "Took you long enough," gripes GoGo.

"I couldn't find a good spot!"

"There's, like, ten other cars here. There are plenty of good spots to park."

"I have a system for everything, GoGo! You know that! Now who's ready to visit to our convicted professor?" The rhetorical question is met with a wry smile and the resounding pop of bubble gum. "Right. Let's go in, I guess."

"Do you guys visit Callaghan often?" asks Tadashi.

"Only a handful of times," admits GoGo. "Except for Hiro."

"Yeah, Hiro hasn't seen Callaghan since they arrested him. Before you… came into our lives," Wasabi shoots him an apologetic smile, "Hiro wouldn't even utter his name. He's not mad at Callaghan anymore, but I don't think he'll ever forgive him for what he did."

Tadashi can't say he blames him. He had told Hiro not to blame Yokai before he fell, but even he would have a hard time not seeing a masked stranger in an overcoat as the villain, especially if he was partially responsible for trapping him in an alternate world. "Does he know that you guys come here?"

"Yeah, and we invite him every time. But he never comes."

"So what will he think when we tell him I came here?"

"He'll probably go ballistic," answers GoGo. "But he'll get over it."

Once they enter the prison, the college students make their first stop at the front desk, where they leave behind any prohibited items. When they have to show their IDs, Wasabi and GoGo show their driver's licenses. Tadashi is asked to put his hood down when he shows them an old student ID that belonged to his alternate self. He doesn't ask how they managed to snag it from Hiro, but he has a feeling that it was GoGo's doing. The guards lead them through a series of halls until they're in a completely isolated area.

"They're keeping him in solitary confinement?" Tadashi whispers in astonishment.

GoGo gives him a look as she pops her gum for the umpteenth time. "He built a portal that destroyed the Krei Tech building and nearly swallowed up San Fransokyo."

"… Okay. Point taken."

They finally reach the door. And on the other side is Callaghan.

"Only one visitor at a time."

Wasabi and GoGo move aside, leaving Tadashi to face this task alone. "I-I guess I'm going in. See you guys in a few minutes." He doesn't take a single step. He reaches up to grasp the comfort of his hat only to be met by his unkempt hair. Oh, right. His hat is still in the other world.

A hand claps itself on his shoulder, and he looks down to see GoGo giving him a reassuring smile. Well, what's considered a smile in her case. "We're not going anywhere, Tadashi. We'll be right here waiting for you." Wasabi gives him a thumbs-up. With his friends' encouragement, Tadashi finally takes the first few steps inside Callaghan's cell.

It's dark, except for the square of light in which the former professor resides. The man himself has his back to the entrance, and he's leaning over in his chair, big, calloused hands running through salt-and-pepper hair. The walls are a dark, hoary color that bleeds black when the door closes behind him. The sound stops the prisoner's fidgeting, and slowly he turns around. His wrinkly eyes crinkle as they try to discern whoever has entered the cell. "Who's there?"

Little by little, Tadashi shortens the distance between him and Callaghan. As he gets closer, he can just barely make out his own transparent reflection. Apparently Callaghan is considered too dangerous to be kept in a normal jail cell. Once Tadashi is in the light, the older man is on his feet. His face takes on a pallor complexion, his eyes wide as if he's seeing a ghost. Which, Tadashi thinks, is probably exactly what he's experiencing. "T-Tadashi? But I thought I… How is this possible?"

"It's not what you think, Professor."

Callaghan suddenly shrinks into himself, sinking back into the chair where he was previously wallowing. "I don't deserve to be called that, especially by you." It breaks Tadashi's heart seeing someone he's admired for so long look so broken. But he has no time to make him feel better. The other Tadashi is still dead, and there's nothing anyone can do about it.

"Professor, I'm not Tadashi."

Callaghan looks up again, befuddled. "What?"

"I mean, I am Tadashi, but not this world's—look, it's a long story. I got sent here by Yokai—the other you—but not on purpose. I was trying to help you—other you—rescue your daughter, but the portal was too unstable and I got sucked in. Now I'm here and there's another villain—Sunfire—out there who's trying to rebuild the same portal that got me here, and we—me and Big Hero 6—think that he needs me in order to make it work properly. Long story short, we need your help to catch the guy before he does something drastic."

Callaghan stands and his eyes roam the younger man's form analytically. He crosses his arms, intrigued. "An alternate world, huh? So someone figured out the Einstein field equation for interdimensional travel. So who is this… Sunfire?"

At first, Tadashi is too lightheaded to reply. He should have known someone as erudite as Callaghan would be more open-minded about this. He barely even reacted when he mentioned he's from another world. Callaghan just accepted it as fact. It's one of the things the young man admires about him. Right now, the older man's eyes retain a sharp glint that Tadashi recognizes as scientific curiosity.

"We don't know his real identity. All we do know is that he's extremely clever and he knows his stuff. He stole the portal's apparatus from Krei Tech and who knows what else. He also rebuilt the portal by himself and somehow figured out how to get it to work, hence…" He gestures to himself.

Callaghan plants a fist under his chin pensively. "What did you do when you were helping the other Callaghan rebuild the portal?"

"I assume the same thing you did when you rebuilt it over the Krei building. We were just trying to make it functional enough to retrieve Abigail, not fix it. It was too unstable for anything practical. But then I got trapped there for… I don't even know how long. I think time works differently in the other dimension than it does in other realities." When he says this, Tadashi can't help thinking about all the time he lost in his world. How long have Hiro and his friends been waiting for him to come back? How long has Cass mourned for him? How long until he can go back…?

What Callaghan says next breaks him out of his morose thoughts: "Then something must have happened to you while you were stuck in that dimension, something that goes beyond Einstein's space-time equations."

"What do you mean?"

"You should be dead, Tadashi." The bluntness of his statement stuns the young man into silence. "Tadashi, the portal is essentially an artificial wormhole, and a wormhole is essentially a three-dimensional tunnel that bypasses space and time. The reason why the portal never worked in the first place was because… well, it's unnatural. It's an artificial construct that was forced to take shape and take in matter that doesn't belong.

"I was there when Krei's scientists built the prototype, and I saw the composition of the space within the wormhole. Organic matter cannot survive long exposure to the properties within that dimension. The electromagnetic plane is filled with negative, cosmic matter, which makes it erratic and the state within unpredictable, and anything extremely dense breaks down into something more insubstantial. It's similar to a black hole; whatever goes in gets pulled apart and it doesn't come back out the same way. At least that's what we thought. When the first portals were made, anything smaller than a baseball cap went in and out the other side unharmed. It was safe to assume anything inorganic could go in, but organic matter was another story. That's when Krei hired a test pilot. My daughter was the unfortunate candidate chosen…" Callaghan's countenance took on a murderous glare. "Needless to say it didn't work. The only reason Abigail survived after being in there so long is because the pod and her suit were designed with a shield that blocked out the electromagnetic forces within the wormhole. Of course, she wouldn't have gotten stuck there in the first place if Krei hadn't—"

"Professor, please stay focused."

Callaghan abashedly coughs into his fist. It seems he's still not over what happened three months ago. "Right, excuse me."

"Didn't Hiro go into the wormhole to save Abigail? He came out pretty much unharmed."

"He wasn't in there as long as Abigail, and because he came out unharmed it's further proof that there are still many things we don't know about wormholes and the spaces between them. Which is why the fact that you not only survived a trip through a wormhole but also traveled from your world to ours without any repercussions is a scientific marvel. To do something so unfounded in such an unstable plane of existence with no protection... Either Sunfire fixed the space-time equation or…" Callaghan pauses.

"Or what?"

He shakes his head, laughing. "The idea itself… it's ridiculous! Unless..."

"Unless what?" The former professor paces within his cell, his eyes tracing invisible equations along the walls of his prison. The suspense is killing Tadashi. He wishes the physics expert would reach whatever conclusion he's coming to faster. Before he realizes it, he's on the glass, his hands grasping for the answers Callaghan refuses to give him. "What are you thinking, professor?"

"Tadashi, you said you don't know how long you were within the portal, right? Or what is was like there?"

"No, I don't. It was… hard to tell time there." The drill of pain that comes with thinking about that place is already giving him a migraine. Colors blot his vision and his stomach churns. He leans against the glass wall, nauseated. "I can't remember anything, professor. It… hurts."

"What about Sunfire? What did you do when he found you?"

This time, remembering hurts less, but his temple continues to throb. "I don't remember the exact details, but… something weird happened when I ran away from Sunfire. He should have been able to catch me…" He mumbles the last part to himself. "One moment I'm in his lab, listening to him drone on about density matrixes and whatnot, then the next I'm… outside…" He pauses. The look on Callaghan's face frightens him. He looks… elated. "Professor?"

"I believe Sunfire is right, Tadashi. You are the solution to the interdimensional travel."

"But… how?!"

"There's a mechanism in quantum theory that's called the 'Everett phone'. Basically, it's a device that allows someone to communicate or even travel traversable wormholes into other universes. It's based on a theoretical nonlinear equation, and I believe that's essentially what happened to you. Your time in the other dimension must have been long enough to allow the electromagnetic energy in that plane to sync with the electromagnetic pulses in your brain, and the cosmic matter spread throughout your body, which converted the negative particles into positive ones, allowing you to travel into this world unharmed. You became the Everett phone."

His head pounds harder and harder as he reevaluates Callaghan's hypothesis. Even though quantum physics is outside his scope of knowledge, he still understands the basics, and the weight of his mentor's words literally sends Tadashi on his knees. "Professor… what are you saying?"

"Tadashi, you may have the power… to freely travel throughout space and time."

Suddenly, it feels like time has stopped and the floor has collapsed from under him. He's no longer in his old professor's cell. Instead, he's in the dilapidated warehouse where he'd run into Sunfire. The villain is wearing the suit, but there is no fire and no mask to hide his identity. But even without the Kabuki mask, his face is still too fuzzy for Tadashi to make out. As he struggles to get clearer look at his abductor, the drill of pain increases tenfold. Slowly, Sunfire approaches him and reaches out, and before he knows it he's outside the warehouse. But he doesn't stop to marvel at this miracle and instead picks himself up and runs out to the street, straight into a blue sonata.

The last thing he hears before the peaceful oblivion of nothingness pulls him under is Callaghan urgently calling for the guards.

A/N: Please don't call me out on the science behind this chapter. I majored in zoology, not astrophysics. I did a lot of research about interdimensional travel while writing this story and I still don't understand most of it. Everything I wrote in this chapter is based on what I do understand, for the most part, and there will be chapters just like it that involve other fields of science that I also have a hard time comprehending. But I will admit I did have fun reading about it, and it made writing this story a fun challenge. Science is awesome :)

I hope you all enjoyed it!